It wasn't just teary-eyed viewers who were left speechless after Kellie Pickler's flawless, dramatic freestyle performance with Derek Hough on Monday night's Dancing with the Stars finals. The country starlet herself was also at a loss for words.

"I just feel like I let all of my walls down and I just got out there and just did my little dance," Pickler, 26, told PEOPLE backstage after her performance. "I just let myself go. There was a freedom, in a sense, that I felt. I really don't even know how to put it into words. Regardless of what happens tomorrow, I feel like I've accomplished so much being here."

Hough, 28, who admitted he and Pickler struggled with the routine during rehearsals, said, "We were super, super nervous, but right before we went on there, I kind of gave Kellie a little pep talk. I was just like, 'This is your dance. There is nobody here that can do this dance but you. This is what you're meant to do.' "

Of the beautiful ballad they danced to – Labrinth and Emeli Sandé's "Beneath Your Beautiful" – Hough said, "We were going to go with a country song, and then I heard this song, and it's like No. 1 in the U.K. When I heard the song, I immediately thought, 'This is Kellie. Seeing into beautiful.' "

Added the ballroom pro, "We all know Kellie's beautiful. We all know that she's fun and light. But see beneath that. Let's see the real you. It felt right."